acpi: Support generation of interrupt descriptor

Add a function to write an interrupt descriptor to the generated ACPI
code.

Signed-off-by: Simon Glass <sjg@chromium.org>
Reviewed-by: Wolfgang Wallner <wolfgang.wallner@br-automation.com>
Reviewed-by: Bin Meng <bmeng.cn@gmail.com>
diff --git a/test/dm/acpigen.c b/test/dm/acpigen.c
index 9ff9b68..a4adfbf 100644
--- a/test/dm/acpigen.c
+++ b/test/dm/acpigen.c
@@ -8,8 +8,10 @@
 
 #include <common.h>
 #include <dm.h>
+#include <irq.h>
 #include <malloc.h>
 #include <acpi/acpigen.h>
+#include <acpi/acpi_device.h>
 #include <asm/unaligned.h>
 #include <dm/acpi.h>
 #include <dm/test.h>
@@ -70,3 +72,33 @@
 	return 0;
 }
 DM_TEST(dm_test_acpi_emit_simple, 0);
+
+/* Test emitting an interrupt descriptor */
+static int dm_test_acpi_interrupt(struct unit_test_state *uts)
+{
+	struct acpi_ctx *ctx;
+	struct udevice *dev;
+	struct irq irq;
+	u8 *ptr;
+
+	ut_assertok(alloc_context(&ctx));
+
+	ptr = acpigen_get_current(ctx);
+
+	ut_assertok(uclass_first_device_err(UCLASS_TEST_FDT, &dev));
+	ut_assertok(irq_get_by_index(dev, 0, &irq));
+
+	/* See a-test, property interrupts-extended in the device tree */
+	ut_asserteq(3, acpi_device_write_interrupt_irq(ctx, &irq));
+	ut_asserteq(9, acpigen_get_current(ctx) - ptr);
+	ut_asserteq(ACPI_DESCRIPTOR_INTERRUPT, ptr[0]);
+	ut_asserteq(6, get_unaligned((u16 *)(ptr + 1)));
+	ut_asserteq(0x19, ptr[3]);
+	ut_asserteq(1, ptr[4]);
+	ut_asserteq(3, get_unaligned((u32 *)(ptr + 5)));
+
+	free_context(&ctx);
+
+	return 0;
+}
+DM_TEST(dm_test_acpi_interrupt, DM_TESTF_SCAN_PDATA | DM_TESTF_SCAN_FDT);